Known engine control systems have utilized conventional temperature sensors disposed in engine exhaust systems to measure exhaust gas temperatures. The temperature measurement of the exhaust gases can be utilized by an engine controller for various purposes including: (i) determining an operating efficiency of an emission catalyst, and (ii) determining when to purge an emission catalyst of stored exhaust gas constituents.
Known engine control system also utilize separate exhaust gas sensors, such as oxygen sensor for example, for controlling air-fuel delivery to the engine cylinders. Generally, a first exhaust gas sensor is disposed upstream of an emission catalyst and a second exhaust gas sensor is disposed downstream of the emission catalyst.
The inventors herein have recognized that it would be advantageous to measure exhaust gas temperatures with the exhaust gas sensors, thereby eliminating the need for a separate temperature sensors in vehicle exhaust systems.